Excavation bit for a drilling apparatus

a drilling apparatus and excavating bit technology, applied in the field of excavating bit, can solve the problems of more cutters, limited bore size of operators, and greater torque and thrust to be applied to the bit,

Inactive Publication Date: 2003-03-18
MOLLOY ANTHONY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

Preferably affixed or rotatably attached to the main body is a stabiliser to assist the excavation bit keeping to a desired path.

Problems solved by technology

The main disadvantages with these types of bits is that to produce a larger hole will require more cutters, and as such a greater torque and thrust must be applied to the bit.
Thus an operator is limited in the size of bores that can be excavated by the amount of power available from the driving equipment.

Method used

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  • Excavation bit for a drilling apparatus
  • Excavation bit for a drilling apparatus
  • Excavation bit for a drilling apparatus

Examples

Experimental program
Comparison scheme
Effect test

embodiment 32

FIG. 5 illustrates a reaming embodiment 32 similar to that of FIG. 1, showing the surface to be reamed 21 after the pilot hole 29 is drilled. Pilot hole 29 also acts as a guide for the bit 32, as drill rods and drive shaft 12 are pulled through the pilot hole 29. The axes 47 and 48 of the carriers 14 and 15 are inclined above the first transverse axis 49. This allows the tips of the cutters 25 to angle toward each other and to engage as close to the pilot hole 29, without contacting the drill rod or drive shaft 12. By rotating drive shaft 12, without any externally imposed upward thrust (in direction of arrow 4), the bit 32 will thrust in the direction of arrow 4 due to the contact of the cutters 25 with the rock surface 21, and the contra-rotation of the carriers 14 and 15.

second embodiment

In FIG. 6 of the accompanying drawings there is diagrammatically depicted a In this embodiment the bore engaging end of the drive shaft 12 is provided with a pilot hole bit 74. Other detail of the apparatus is substantially the same in construction and operation as that described above with reference to FIG. 1.

As depicted in FIG. 6, the apparatus includes a pair of upper bearings 63 located about the drive shaft 12 and held in position thereon by means of a bearing retaining nut 64. Bearings 63 engage with the internal annular surface of a bearing carrier 62 which is bolted or otherwise secured to the main body 11. A seal carrier 60 is bolted or otherwise secured to the bearing carrier 62 and includes an annular seal 61. Similarly, the other (internal) end of the bearing carrier 62 includes an annular seal 61 which bears against the surface of the drive shaft 12. The main body 11 includes a further annular seal 69 about its periphery near the bore engaging end. Seal 69 bears agains...

fourth embodiment

FIG. 10 illustrates a fourth embodiment wherein the angle .theta. is approximately 120.degree.. In this embodiment, there are provided additional cutting teeth 25, which are mounted on side surfaces of the carrier 14, or if desired, they could also be mounted onto cover plate 73. These additional cutters assist in providing additional stability to the excavation bit, as it is excavating.

The angle .theta. affects the relationship between the torque in drive shaft 12 and the pushing effect of the cutting teeth 25 against the rock. If the angle .theta. high, but less than 180.degree. then the main body 11 will rotate by virtue of the reaction forces resulting from cutter engagement, to produce a moment about the longitudinal axis 22. As the angle .theta. decreases in size, the pushing effect increases and rotation speed increases. Simultaneously, as the angle .theta. decreases, so does the magnitude of thrust (in direction of arrows 4 (FIG. 3) or arrow X (FIG. 9), produced by the contr...

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PUM

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Abstract

The invention provides an excavation bit, which is constructed from either a single or double carrier. If two carriers are present the carriers are contra-rotating. By the off setting of the axes of rotation of single or dual carriers from a longitudinal axis of the bit, and by driving to carriers to rotate, a ground engaging thrust is produced, as well as the rotation of the excavation bit in the ground as a consequence of the rotation of the carriers, and not vice versa as is the case with prior art. By the invention, there can result sufficient thrust on the bit, by the rotation of the carriers, so that the need to apply thrust down the bore via the drill rod is reduced or eliminated. As a result of the invention the number and or size of the ground engaging tools are not a function of the bore diameter to be drilled. Thus as the excavation bit is scaled up for larger diameter bores more ground engaging tools and or an increase in their size is not required. By the invention, thrust applied (either via the drill rod or from the rotation of the carriers) is thought to be, through a quasi lever system, multiplied at some of the ground engaging tools in the radial direction. That is the total thrust in the longitudinal axis direction (whether externally applied or resultant from the contra-rotation of the carriers), is multiplied so that the outward forces exerted (by the cutters onto the rock surface in the region approaching perpendicular to the longitudinal axis of the bore) is thought to be significantly higher than the magnitude of the total thrust.

Description

I. FIELD OF THE INVENTIONThe present invention relates to an excavation bit which is used to bore rock or earth surfaces.II. BACKGROUND OF THE INVENTIONThe prior art drilling apparatus use an excavation bit for conventional (near surface to far surface) drilling, or a reverse reaming bit for far surface to near surface drilling, comprising one or more ground engaging formations mounted on the excavation bit. The ground engaging formations can be either drag, button, tooth, disc, point attack or other cutters on the bit to excavate rock. The main disadvantages with these types of bits is that to produce a larger hole will require more cutters, and as such a greater torque and thrust must be applied to the bit. Thus an operator is limited in the size of bores that can be excavated by the amount of power available from the driving equipment. The operation of conventional bits is performed by the revolving of the body of the bit, which then causes the cutters and carrier to rotate becau...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): E21B4/00E21B4/16E21B10/26E21B10/16E21B10/28E21B10/08
CPCE21B4/16E21B10/28E21B10/16E21B10/08
Inventor MOLLOY, ANTHONY
Owner MOLLOY ANTHONY
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